In the existing Institute of Electrical and Electronics Engineers (IEEE) 802.11 standard, an access point access point (AP) can support a maximum of 2007 access devices (or referred to as Stations, STAs for short, which, in the 802.11 standard, refer to devices that support the 802.11 protocol). Actually, STAs connected to one AP are restricted by bandwidth of the AP, and a maximum of dozens to hundreds of STAs can be connected to one AP. When there are more users (for example, during a game in a stadium), an AP needs to be added to increase bandwidth resources.
The 802.11ah standard under development uses a free frequency spectrum below 1 GHz to cover a scope of 1 kilometer. The standard is used in application fields such as a smart meter and a smart sensor network. A feature of these applications is that a data amount of a terminal is very small, and a coverage area of an AP is large; therefore, a large number of terminals may be supported. For example, the AP needs to support more STAs. For example, the number of STAs increases to 6000.
However, if the AP is required to support more STAs and a plurality of STAs simultaneously contend for accessing a network, an existing contention mechanism cannot operate. Because an existing biggest contention backoff window is 1023, it is almost impossible to avoid a conflict when thousands of STAs contend for a channel. As a result, it is very difficult for the STAs to access the network, or access of the STAs to the network takes a long period.